In order to allow the CNS to process the request, it is essential to indicate the 13-digit national identification number (matricule number).
A written request must be sent to the CNS in order to change an address. The request can be sent by mail to the "Service Coassurance et signalétique" or by e-mail.
A certificate of residence, issued by the commune of residence, must be joined to the request for a change of address.
As the French communes are not always able to issue a certificate of residence, a declaration of honour certified by the commune of residence can be accepted.
A request for a change of address which contains neither a certificate of residence nor a declaration of honnour cannot be processed by the CNS.
Luxembourg residents do not have to declare their change of residence to the CNS. The Luxembourg commune of arrival proceeds directly to the change in the National registre of physical persons (Registre national des personnes physiques-RNPP).